JP4685683B2 - Magnetic encoder and manufacturing method thereof - Google Patents

Description

  The present invention is used for a magnetic encoder used when detecting the number of rotations (rotation speed) of a rotating body, for example, a device for detecting the number of rotations of a wheel of an automobile or a number of rotations detecting device for a relative rotating bearing. The present invention relates to a magnetic encoder and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, an axial type magnetic encoder employed in a rotational speed detection device for detecting the rotational speed of a vehicle wheel is provided on an annular reinforcing core bar and one surface of the core bar. An annular scale composed of magnets magnetized in multiple directions.

  While this magnetic encoder is fixed to the end of the rotating shaft as a rotating part, a sensor for detecting a change in the magnetic field is disposed close to the annular scale of the magnetic encoder. A change in the magnetic field generated from the annular scale of the rotating magnetic encoder is sensed by a sensor to detect the rotational speed.

  Conventionally, a rubber magnet material is often used as an annular scale in the magnetic encoder as described above, as shown in Patent Document 1 below.

  As the rubber magnet material, a material obtained by dispersing and blending a magnetic powder such as ferrite in a rubber material such as synthetic rubber (magnetic rubber material) is generally used.

  In other words, this magnetic rubber material is vulcanized and molded into multiple poles so that N poles and S poles alternate in the circumferential direction to produce an annular scale molded body. A magnetic encoder is manufactured by baking and fixing to one surface of a core metal through an adhesive.

  On the other hand, in the technical field of magnetic encoders, particularly those for automobiles, improvement in detection accuracy, improvement in productivity, cost reduction, and the like are pursued as much as possible. As one of the countermeasures, as a material constituting the annular scale of the magnetic encoder, a technique using a plastic magnet material as shown in the following Patent Document 2 instead of a rubber magnet that has been widely used conventionally has been studied. ing.

Compared to rubber magnets, plastic magnets have a higher magnetic particle orientation ratio due to magnetic field molding, so they can be expected to improve detection accuracy due to their large magnetic force, and can also be efficiently manufactured by thermoforming. can do.
JP-A-11-281659 JP-A-2005-315782 (Claims)

  By the way, an automobile wheel rotational speed detection device is used under severe conditions such as high temperature, low temperature and muddy water environment, and high salinity environment to prevent freezing. For example, in cold regions, the vehicle may be exposed to a very low temperature of about -40 ° C. when the vehicle is stopped, and conversely, it is exposed to a high temperature of about 120 ° C. due to heat transfer from the engine and the temperature rise of the rotation of the bearing. Sometimes.

  Thus, although the magnetic encoder for automobiles is used even under severe temperature environment, the plastic as the annular scale formed body in the magnetic encoder has a large thermal expansion coefficient with respect to the metal as the core metal, Unlike rubber, because it is inferior in elasticity, a large deformation stress acts on the plastic scale molded body due to the difference in thermal expansion between the two under the above severe temperature environment, and the scale molded body cracks, In some cases, the adhesiveness is lowered, so that there is a problem that the core metal peels off and falls off.

  On the other hand, in order to join and fix the plastic magnet material to the core metal, an insert molding method using the core metal as an insert member, or a plastic magnet material is preliminarily thermoformed into an annular shape to produce an independent scale molded body. In general, a method in which the scale molded body is bonded and fixed to the core metal with an adhesive is generally employed.

  However, in either method, since the plastic magnet material is joined to the metal core via an adhesive, an adhesive application work is required, which increases the number of processes, reduces productivity, and reduces costs. There was a problem of increasing.

  Furthermore, when insert molding is performed by applying an adhesive to the metal core, in addition to the adverse effects of the severe temperature environment described above, internal stress is also generated in the plastic magnet material (scale molded body) by molding shrinkage immediately after thermoforming. For this reason, there is a risk of promoting cracks and peeling of the scale molded body.

  In order to improve the adhesion of the plastic magnet material to the metal core, measures to add special modifiers and measures to use special adhesives have been proposed. It is difficult to adopt at present because of the increase.

  This invention solves the above-mentioned problems of the prior art, can sufficiently secure the adhesion strength of the plastic magnet scale molded body to the core metal, can prevent the molded body from being cracked or cracked, and can further improve the production efficiency. An object of the present invention is to provide a magnetic encoder that can be manufactured well at low cost and a manufacturing method thereof.

  In order to achieve the above object, the present invention provides the following means.

[1] A magnetic encoder provided with an annular cored bar, and an annular scale molded body formed of a plastic magnet material provided on one surface of the cored bar and magnetized in multiple poles in the circumferential direction. Because
A plurality of radial grooves extending in the radial direction and opening in the inner diameter direction are formed side by side in the circumferential direction on one surface of the cored bar,
A magnetic encoder, wherein a filling molding portion made of a plastic magnet material filled in the radiation groove is formed integrally with the scale molding.

  [2] The magnetic encoder according to item 1, wherein an adhesive is not provided between the core metal and the scale molded body.

  [3] The item 1 or 2 above, wherein the inner surface of the side wall of the radiation groove is disposed on virtual radiation extending radially from the center of the core bar, and the width of the radiation groove becomes narrower toward the inner diameter direction. The magnetic encoder according to 2.

  [4] The magnetic encoder according to any one of [1] to [3], wherein a peeling prevention protrusion is provided on the inner surface of the side wall of the radiation groove to prevent the scale molded body from peeling in the axial direction. .

  [5] The above-mentioned items 1 to 5 are provided, wherein a rising piece is provided on an outer peripheral edge of the core metal to be engaged with an outer peripheral end surface of the scale molded body to prevent the scale molded body from peeling in the axial direction. 5. The magnetic encoder according to any one of 4 above.

  [6] A wrap-molded portion formed of a plastic magnet material is integrally formed on the inner peripheral portion of the scale molded body, and the wrap-formed molded portion passes through the inner peripheral edge from one surface of the core bar and the core. 5. The magnetic encoder according to any one of items 1 to 4, which is disposed so as to wrap around the other surface of the gold.

[7] A magnetic encoder comprising an annular cored bar, and an annular scale molded body that is provided on one surface of the cored bar and is made of a plastic magnet material that is magnetized in multiple poles in the circumferential direction. A method for manufacturing
Obtaining a ring-shaped cored bar in which a plurality of radial grooves extending along the radial direction and opened in the radial direction are arranged in a circumferential direction on one surface;
A plastic molded material is used as a molding material, and the cored bar is used as an insert member. By performing injection molding in a magnetic field, a filling molding part is formed by the molding material filled in the radiation groove. Forming a scale formed body integrally therewith to obtain a magnetic encoder.

  According to the magnetic encoder of the above invention [1], a plurality of radiation grooves are formed on one surface of the core metal, a scale molded body is formed on one surface of the core metal, and a filling molded portion is integrally formed with the scale molded body in the radiation groove. Since it forms, a scale molding is structurally fixed to a radiation groove via a filling molding part. For this reason, it is possible to effectively prevent the scale molded body from being peeled off or displaced from the core bar, and can be firmly fixed to a sufficient strength.

  Furthermore, in the present invention, since a radial groove extending in the radial direction and opening in the radial direction is formed in the core metal, and the filled resin portion is filled in the radial groove, the thermal expansion of the core metal and the scale molded body is performed. Generation of cracks and cracks due to the difference can be prevented. That is, when the scale molded body contracts / expands with respect to the core metal, the scale molded body maintains a similar shape and contracts / expands as a whole along the radial direction. As the molded body contracts / expands, it moves in the radial direction along the radial groove. By this movement, it is possible to prevent stress from being concentrated on the scale molded body and the filled resin portion, and to prevent problems such as cracks and cracks from occurring in the scale molded body.

  Moreover, since the magnetic encoder of the present invention can be manufactured by thermoforming capable of mass production such as insert molding, production efficiency can be improved and cost can be reduced.

  According to the magnetic encoder in the above invention [2], since the scale molded body is coated and formed on the core metal without using the adhesive, the production efficiency can be further improved since the step of applying the adhesive can be omitted. This can improve the cost and further reduce the cost.

  According to the magnetic encoder in the above invention [3], the groove width of the radiation groove is formed so as to become narrower toward the inner diameter direction. For example, when the scale molded body is contracted, the filling molding portion narrows the width. While being deformed, it is displaced smoothly and smoothly inward in the radial direction along the radiation groove. On the contrary, when the scale molded body is expanded, the filling molded portion is deformed so as to widen the width thereof, and is smoothly and smoothly displaced radially outward along the radiation groove. In this way, when the kale molded body is contracted / expanded, the filling molded part moves smoothly and smoothly along the radial groove, so that it is possible to prevent a large amount of stress from being generated in the filling molded part and eventually the scale molded body, It is possible to more reliably prevent defects such as cracks and cracks from occurring in the scale molded body.

  According to the magnetic encoder in the invention [4], since the protrusion for preventing peeling is provided on the inner surface of the side wall of the radiation groove, the filling molded portion in the radiation groove is locked to the protrusion for preventing separation. It is possible to more reliably prevent the scale molded body from peeling off in the axial direction with respect to the core metal, and the scale molded body can be tightly fixed to the core metal in a more stable state.

  According to the magnetic encoder in the above invention [5], the rising piece is provided on the outer peripheral edge of the cored bar, and the rising piece is engaged with the outer peripheral end surface of the scale forming body. Can be more reliably prevented, and the scale molded body can be tightly bonded to the core metal in a more stable state.

  According to the magnetic encoder in the above invention [6], the wrap-around molded part formed integrally with the scale molded body is formed so as to wrap around from the inner peripheral part of one surface of the cored bar to the inner peripheral part of the other surface. By engaging this wrap-around molded part with the core metal, the scale molded body can be prevented from peeling in the axial direction with respect to the core metal, and the scale molded body can be further prevented from peeling off. Thus, it can be tightly bonded in a more stable state.

  Since the said invention [7] specifies one form of the method of manufacturing the magnetic encoder which has the structure of the said invention [1], the magnetic encoder which has the same effect as the above can be manufactured.

<First Embodiment>
1 and 2 are views showing a magnetic encoder (1) according to a first embodiment of the present invention, and FIGS. 3 to 7 are views showing a core metal member (10) applied to the encoder (1). . As shown in these drawings, the magnetic encoder (1) of the first embodiment includes a substantially annular cored bar member (10) and an annular scale molded body (40) made of a plastic magnet material. ing.

  The metal core member (10) is a metal that integrally includes an annular plate-shaped metal core (20) and a cylindrical attachment piece (30) provided in a rising shape on the outer peripheral edge of the metal core (20). It consists of a press-formed product made of the product.

  The core member (10) is formed, for example, by subjecting a metal plate such as a magnetic steel plate to press working such as punching or drawing.

  Further, as a material of the cored bar member (10), a metal material having magnetism is used in order to be able to adsorb to the plastic magnet material and not to deteriorate the magnetic characteristics with the magnet material. Considering the formability in press working in particular, it is preferable to use a low carbon steel plate such as a cold rolled steel plate (SPCC) as the material of the cored bar member (10).

  On one surface of the annular cored bar (20) of the cored bar member (10), a large number of radial grooves (21) extending along the radial direction are formed side by side at a predetermined pitch in the circumferential direction.

  The radial groove (21) has a rectangular cross-sectional shape, and an end portion in the inner diameter direction is opened inward, and an end portion in the outer diameter direction is formed from an outer peripheral edge portion of the core metal (20). Is also closed on the outside by being arranged on the inside.

  Further, as shown in FIGS. 6 and 7, the radiation groove (21) corresponds to the virtual radiation (L) whose inner surface (22) of both side walls extends radially from the center (C) of the core metal (20). It arrange | positions in this way, and it is formed so that the width | variety of a radiation groove (21) may become thin gradually as it goes to an internal diameter direction. In this way, the inner surface (22) of both side walls is formed in a taper shape, and the radiation groove (21) is formed in a substantially trapezoidal groove or fan-shaped groove shape in a plan view shown in FIG.

  In the present embodiment, when the number of the radiating grooves (21) is set to the same number as the total number of N poles and S poles of the scale molded body (40) described later, the magnetism due to the formation of the radiating grooves (21). This is preferable because the influence on the characteristics is made uniform.

  The formation method of the radiation groove (21) is not particularly limited, and cutting, pressing, electric discharge machining, and the like can be used. Among them, it is preferable to use pressing in consideration of mass productivity.

  When the radial groove (21) is formed by pressing, a punch mold in which a large number of convex portions corresponding to the shape of the groove (21) are uniformly arranged along the circumferential direction can be used. All the radiation grooves (21) can be formed simultaneously. In this case, an annular cored bar (20) made of a metal plate such as a steel plate is sandwiched from above and below by a pair of punches, and is punched into the punch mold to be pressed (coined). .

  In addition, you may form a radiation | emission groove | channel (21) by half punching like the 2nd modification explained in full detail behind.

  In the case of coining, the groove depth of the radiation groove (21) is preferably set to 25 to 50% with respect to the thickness of the core metal (20). That is, when the radiating groove (21) is too shallow, the plastic magnet material constituting the scale molded body (40) cannot be sufficiently filled in the groove (21) and entangled as described later. There exists a possibility that the adhesive strength with respect to the metal core (20) of a body (40) may fall. On the other hand, when the radiating groove (21) is too deep, the degree of processing becomes large, warping or deformation may occur, and the dimensional accuracy may be reduced.

  As shown in FIGS. 1 and 2, an annular scale molded body (40) made of a plastic magnet material is formed on one surface of the core metal (20).

  Further, a wraparound portion (41) made of a plastic magnet material is formed integrally with the scale molded body (40) on the inner peripheral portion of the scale molded body (40). The wrap-around part (41) is arranged from the inner peripheral edge of one surface of the core metal to the inner peripheral edge of the other surface through the inner peripheral edge of the core metal.

  Furthermore, in each radiation groove (21), a filling molding part (42) made of a plastic magnet material is formed integrally with the scale molding (40).

  In this embodiment, the plastic magnet material constituting the scale molded body (40) including the molded parts (41) and (42) is composed of a resin composition in which a plastic material is mixed as a binder with the magnetic powder. The

  As the magnetic powder, rare earth magnetic powders such as neodymium and samarium are used in addition to ferrite magnetic powders such as strontium ferrite and barium ferrite.

  As the plastic material used as the binder of the magnetic powder, a thermoplastic resin material for injection molding is used. Needless to say, the resin material to be used is appropriately selected in consideration of properties such as strength, heat resistance, chemical resistance, and magnetic properties, moldability, compoundability, and cost. For example, in this embodiment, a resin material such as polyamide 6 (PA6), polyamide 12 (PA12), polyamide 612 (PA612), polyphenylene sulfide (PPS), or the like can be preferably used.

  In the present embodiment, the content of the magnetic powder in the plastic magnet material is preferably set to 45 to 75% by volume. That is, when the content of the magnetic powder is too small, the magnetic characteristics are inferior and multipolar magnetization becomes difficult, and there is a possibility that the detection accuracy at the time of detecting the rotational speed described later is lowered. On the other hand, when the content of the magnetic powder is too large, the amount of the binder resin is relatively reduced, and thermoforming becomes difficult and the strength of the molded body may be reduced.

  In the present embodiment, the magnetic encoder (1) is manufactured by insert molding using the plastic magnet material. That is, injection molding is performed in a magnetic field without using an adhesive with the plastic magnet material as a molding material and the cored bar member (10) as an insert member. As a result, as shown in FIGS. 1 and 2, a scale molded body (40) composed of a plastic magnet material in a region from one surface of the cored bar (20) through the inner peripheral edge to the inner peripheral edge of the other surface. ) And the wraparound molded part (41) are integrally formed, and the filling resin part (42) made of a plastic magnet material is formed in each radial groove (21) of the core metal (20). 40).

  The insert molded product thus obtained is demagnetized and then subjected to predetermined multipolar magnetization using a separately prepared magnetizing device, thereby producing a scale molded body of plastic magnet material as shown in FIG. (40) is magnetized in multiple poles so that N and S poles alternate in the circumferential direction. Thereby, a magnetic encoder (1) is manufactured.

  When this magnetic encoder (1) is used as a rotational speed detecting device for a rolling bearing or the like, the cylindrical mounting piece (30) of the cored bar member (10) is press-fitted into a rotating shaft portion such as a bearing inner ring in an externally fitted state. While being fixed, a sensor (not shown) for detecting a change in the magnetic field is arranged close to the scale molded body (40) of the magnetic encoder (1). And the change of the magnetic field which arises from the scale molded body (40) of the magnetic encoder (1) rotating in synchronization with the rotating shaft is sensed by the sensor, and the rotational speed is detected.

  As described above, according to the magnetic encoder (1) of the present embodiment, a large number of radial grooves (21) extending in the radial direction are formed on one surface of the core metal (20) at a predetermined pitch in the circumferential direction. A plastic magnet scale molded body (40) is formed on one side, and a plastic magnet filling molded part (42) is formed integrally with the scale molded body (40) in each radiation groove (21). For this reason, the scale molded body (40) is mechanically fixed to the radiation groove (21) through the filling molding portion (42). For this reason, it can prevent effectively that a scale molded object (40) peels to an axial center direction from a core metal (20), or position shift to the circumferential direction, and can acquire the outstanding adhesion performance. In particular, since the scale molded body (40) is in close contact with the cored bar (20) also by magnetic attraction, this magnetic attraction action can be combined to more reliably prevent peeling in the axial direction.

  Furthermore, in this embodiment, the wrap-around molded part (41) formed integrally with the scale molded body (40) is formed so as to wrap around from the inner peripheral part of one surface to the inner peripheral part of the other surface. Therefore, even when this wraparound portion (41) is engaged with the metal core (20), the scale molded body (40) is prevented from peeling off in the axial direction with respect to the metal core (20). The scale molded body (40) can be prevented from being peeled off more securely and can be tightly joined in a stable state.

  Moreover, in this embodiment, since the magnetic encoder (1) is manufactured by thermoforming capable of mass production such as insert molding, production efficiency can be improved and cost can be reduced.

  Furthermore, in this embodiment, without using an adhesive, insert molding is performed to coat and form the scale molded body (40) on the core metal (20), so the step of applying the adhesive can be omitted. The production efficiency can be further improved and the cost can be further reduced.

  Moreover, in this embodiment, the malfunction by the difference in the thermal expansion coefficient of the scale molded body (40) including the wraparound molded part (41) and the filling molded part (42) and the core metal (20) is surely prevented. Can do. That is, when the scale molded body (40) contracts greatly after molding with respect to the core metal (20) due to temperature environment change or molding contraction immediately after thermoforming, the scale molded body (40) can follow the core metal (20). There is a possibility that the scale molded body (40) may crack or peel. Therefore, in the magnetic encoder (1) of the present embodiment, a number of radiation grooves (21) extending in the radial direction and opening in the inner diameter direction are formed in the core metal (20) at a predetermined pitch in the circumferential direction. Since the filling resin portion (42) is formed in the groove (21), even if the scale molded body (40) contracts with respect to the core metal (20), the scale molded body (40) is generally diametrically dimensioned. It shrinks while maintaining a similar shape so that becomes smaller. That is, since the scale molded body (40) shrinks as a whole along the radial direction, the filling molding part (42) in the radiation groove (21) is formed into the radiation groove as the scale molded body (40) contracts. It moves in the inner diameter direction along (21). Because of this movement, the difference in thermal expansion is absorbed without difficulty, so stress does not concentrate on the scale molded body (40) and the filling resin part (42), and cracks and cracks are generated in the scale molded body (40). It is possible to reliably prevent the occurrence of such troubles.

  On the contrary, when the scale molded body (40) expands with respect to the core metal (20) due to a change in temperature environment or the like, the scale molded body (40) expands in the entire radial direction, so that the radiation groove (21). The inner filling molding part (42) moves in the outer diameter direction along the radial groove (21) with the expansion of the scale molding (40), and the thermal expansion difference is absorbed without difficulty. For this reason, stress does not concentrate on the scale molded body (40) and the filling resin portion (42), and the scale molded body (40) and the like can be reliably prevented from being broken and cracked. be able to.

Here, in this embodiment, the behavior and dimensional change at the time of contraction in the filling molding part (42) in the radiation groove (21) will be described in detail. First, as shown in FIG. 8, the temperature of “Δt” is set assuming that the thermal expansion coefficient of the plastic magnet material constituting the scale molded body (40) of the present embodiment is “α” and the total number of the radiating grooves (21) is “2n”. When the diameter of the annular scale (40) decreases from “φD” to “φd” due to the change, the relationship of the following equation (1) is established, and the equation (2) is derived from the equation (1). .
D−d = αD · Δt (1)
d = D−αD · Δt (2)
Further, in the filling molding part (42) in the radiation groove (21), the width of the outer peripheral edge before shrinkage due to the temperature change of “Δt” is “A”, and the width of the outer peripheral edge after shrinkage is “a”. Then, the relationship of the following expressions (3) and (4) is established. However, in these equations, in order to facilitate understanding of the invention, the width dimension of the outer peripheral edge of the filling molded part (42) is assumed to be substantially equal to the distance on the arc line, and the gap between the adjacent radiation grooves (21) Is calculated as “0”.
A = π · D / 2n (3)
a = π · d / 2n (4)
Furthermore, the following equation (5) is derived from the equations (2) and (4).
a = πD (1−α · Δt) / 2n (5)
Then, when the shrinkage ratio (Aa) / A of the outer peripheral edge width of the filling molded part (42) is obtained from the expressions (3) to (5), the following expression (6) is derived.
(A−a) / A = (A−π · D (A−a) / AD (1−α · Δt) / 2n) / A
= 1− (π · D / 2n) (2n / π · D) (1−α · Δt)
= 1- (1-α · Δt)
= Α · Δt (6)
Further, when the formulas (1) and (6) are compared, the shrinkage ratio (D−d) / D in the diameter direction of the scale molded body (40) and the shrinkage ratio of the outer peripheral edge width of the filling molding portion (42). It can be seen that (Aa) / A is equal.

  That is, when the scale molded body (40) contracts, both side surfaces of the filling molded portion (42) are along virtual radiation (L) connecting the both side surfaces and the center (C) of the scale molded body (40). It contracts and deforms so as to be displaced in the inner diameter direction.

  Therefore, in the present embodiment, as described above, the inner surfaces (22) of the both side walls of the radiation groove (21) are arranged on virtual radiation (L) extending radially from the center (C) of the core metal (20). In addition, since the groove width of the radiation groove (21) is formed so as to become gradually smaller toward the inner diameter direction, when the scale molded body (40) contracts, the filling molding part (42) narrows the width. While being deformed as described above, it is displaced radially inward along the radiation groove (21). As described above, when the kale molded body (40) is contracted, the filling molded portion (42) moves smoothly and smoothly along the radial groove (21). Therefore, the filled molded portion (42), and thus the scale molded body (40). It is possible to prevent the generation of a great amount of stress and to more reliably prevent the scale molded body (40) from having a defect such as a crack or a crack.

  On the other hand, when the scale molded body (40) expands relative to the core metal (20), the filling molded part (42) is deformed so as to widen the width thereof, and has a diameter along the radial groove (21). Displaces outward in the direction. Accordingly, during the expansion of the scale molded body (40), as in the case described above, a large amount of stress is not applied to the filling molded part (42) and, consequently, the scale molded body (40), and defects such as cracks and cracks occur. Can be reliably prevented.

  In addition, when forming the side wall inner surface (22) of the radiation groove (21) along the radiation (L), if the number of the radiation grooves (21) is large, the inner end width and the outer end width of the radiation groove (21) And the inclination of the side wall inner surface (22) also becomes gentle. For this reason, when the number of formed radiating grooves (21) is large, the inner end width and outer end of the radiating grooves (21) are not disposed on the radiation (L) without arranging the side wall inner surface (22) of the grooves (21). You may make it form in a parallel groove | channel form with equal width | variety and fixed groove width.

  Specifically, when the number of radiation grooves (21) formed is 30 or less, the side wall inner surface (22) of the radiation groove (21) is disposed on the radiation (L), and the side wall inner surface (22) is inclined. It is good to let it.

  Further, when the radiation grooves (21) are formed at equal intervals as in the present embodiment, the shrinkage amount of the resin filling portion (42) in each groove becomes smaller when the number of grooves is larger. It can be made small, and it can prevent more reliably that a crack and peeling generate | occur | produce.

<First Modification>
9 and 10 are perspective views showing a cored bar member (10) of a magnetic encoder which is a first modification of the present invention. As shown to both figures, in this embodiment, the radiation | emission groove | channel (21) of the metal core (20) in the metal core member (10) is formed in the dovetail shape. That is, the inner surfaces (22) of both side walls of the radiating groove (21) are formed in an inclined surface inclined inward, and the opening width of the radiating groove (21) is formed narrower than the groove bottom width. And the opening edge part of the both-sides wall in a radiation groove (21) is comprised as the protrusion part (25) for peeling prevention which protrudes inside a groove | channel. Other configurations are the same as those in the above embodiment.

  In the magnetic encoder using the cored bar member (10) with this configuration, the filling molding part (42) in the radiation groove (21) is locked to the peeling prevention protruding part (25). 40) can be more reliably prevented from peeling in the opening direction of the radial groove (21), that is, in the axial direction with respect to the metal core (20), and the scale molded body (40) can be more stably maintained. It can be tightly fixed to the metal core (20).

  In the first modified example, the peeling preventing protrusion (25) is formed continuously in the length direction of the radiation groove (21). However, the present invention is not limited to this, and in the present invention, the radiation groove (21 ) May be formed on a part of the inside of the bracket.

  Moreover, in this invention, when forming the protrusion part for peeling prevention (25) in the side wall side surface of a radiation groove (21), as the formation method, the flat part between the radiation grooves in the one surface side of a metal core (20) is used, for example. It is possible to employ a method in which the pressed meat is moved in the groove direction by partial pressing by press working to form the peeling preventing projection (25).

<Second Modification>
FIG. 11 is a perspective view showing a part of a magnetic encoder (1) according to a second modification of the present invention, and FIG. 12 is a perspective view showing a part of a cored bar member (10) applied to the second modification. is there. As shown in both drawings, in the second modification, the radial groove (21) in the cored bar (20) of the cored bar member (10) is formed by half punching. That is, in the above embodiment, the radiating groove (21) is formed by pressing (coining). However, in the second modification, the flesh of the groove portion pressed by the radiating groove (21) by the pressing punch is used as the back surface. It is formed by half punching that plastically flows to the side (the other side). Other configurations are the same as those in the above embodiment.

  When the radiation groove (21) is formed by half punching as in the second modification, the groove depth is about 90% of the thickness of the core metal (20) while maintaining a predetermined accuracy. Can be formed. In addition, when the radiation groove (21) is formed by coining as in the above embodiment, the groove depth is limited to about 50% or less with respect to the thickness of the core metal (20) as described above. .

  Further, in the magnetic encoder (1) of the second modified example, the built-up portion (11) is formed on the other surface side of the core metal (20) corresponding to the radiation groove (21). The wrap-around part (41) of the scale molded body (40) coated so as to wrap around from the one side to the other side of the gold (20) reaches the outer end step part (12) of the build-up part (11). It is good to form so as not to. That is, as shown in FIG. 13, the wrap-around part (41) is formed to a position exceeding the outer end step part (12) of the bulge bulge part (11) on the other side of the core metal, and the wrap-around part (41) is formed. ) To cover the outer end stepped portion (12), when the scale molded body (40) contracts due to the resin shrinkage described above, the wraparound formed portion (41) engages with the outer end stepped portion (12). This makes it impossible to follow the contraction behavior. For this reason, a great amount of deformation stress is generated around the stepped portion of the wraparound portion (41), and cracks and cracks may occur. Accordingly, it is preferable that the wraparound portion (41) does not cover the outer end step portion (12) of the build-up portion (11) on the other side of the core metal.

  However, in the present invention, it is not always necessary to form the wraparound molded part (41), and the resin molded body is formed only on one surface side of the core metal (20) without wrapping the resin on the other surface side of the core metal (20). (Scale molded body) may be formed.

Second Embodiment
14 and 15 are perspective views showing a magnetic encoder (2) according to a second embodiment of the present invention. As shown in both drawings, the magnetic encoder (2) of the second embodiment constitutes a part of a sealing device called a pack seal or a hub seal, and the inner diameter side (inner ring side) of the sealing device. The slinger (110) corresponds to the cored bar member (10) of the first embodiment.

  That is, the magnetic encoder (2) of the present embodiment includes a substantially annular slinger (110) and an annular scale formed body (140).

  The slinger (110) is a metal press-molding integrally having an annular cored bar (120) and a cylindrical mounting piece (130) provided in a rising manner on the inner peripheral edge of the cored bar (120). It is composed with goods.

  On one surface (outer surface) of the annular cored bar (120) of the slinger (110), a plurality of radial grooves (121) extending along the radial direction are formed in a row at a predetermined pitch in the circumferential direction. ing.

  As a material for the slinger (110), a metal material having magnetism and good formability can be used as in the first embodiment. In addition to these properties, in consideration of mud water resistance, corrosion resistance, etc., a stainless steel plate such as ferritic stainless steel (SUS430, etc.), martensitic stainless steel (SUS410, etc.) can be suitably used.

  An annular scale molded body (140) is formed on one surface of the slinger (110) so as to cover the one surface. The scale molded body (110) is composed of a plastic magnet.

  Further, a filling molding part (142) made of a plastic magnet material is integrally formed with the scale molding (110) in the radiation groove (121) of the slinger (110).

  Since other configurations are substantially the same as those of the above-described embodiment, the same or corresponding parts are denoted by the same or corresponding reference numerals, and redundant description is omitted.

  Further, the magnetic encoder (2) of the second embodiment is manufactured in the same manner as described above.

  In the magnetic encoder (2) of the second embodiment configured as described above, the cylindrical mounting piece (130) of the slinger (110) is fixed to the bearing inner ring in an externally fitted state, and the slinger (110) The metal core (120) is disposed in the opening between the bearing inner ring and the outer ring with the scale molded body (140) facing outward.

  Further, in a sealing device such as a hub seal having the magnetic encoder (2) of the present embodiment, an outer diameter side slinger is fixed to the bearing outer ring in an internally fitted state, and a seal lip provided on the outer diameter side slinger is provided with the above slinger. It is comprised so that the outer peripheral part of the other surface (inner surface) in the metal core (120) of (110) may be contacted.

  In this sealing device, the magnetic field detection sensor is disposed opposite to the scale molded body (140), and the rotational speed is detected in the same manner as described above.

  In the magnetic encoder (2) in this sealing device, the same effect as described above can be obtained.

  In the magnetic encoder (2) of the second embodiment, when the radial groove (121) is formed on one surface (outer surface) of the core bar (120) of the slinger (110) by pressing, the other of the core bar (120). There is a possibility that a minute build-up portion is formed at a position corresponding to the radiation groove (121) on the surface (inner surface). As described above, since the other surface side of the cored bar (120) is a contact surface with which the seal lip of the outer diameter side slinger is brought into contact, it is desirable to form it flat so that the seal lip can properly contact. For this reason, it is good not to form a radiation groove (121) in the position which the seal lip in a metal core (120) contacts. In other words, it is preferable that the outermost position of the radiation groove (121) is arranged inside the contact position of the seal lip.

  In particular, when the radial groove (121) is formed by half punching pressing, the flesh of the groove pressed by the punch moves greatly to the other surface side (inner surface side), and a large build-up portion is formed. It is preferable to set the outermost position of the radiation groove (121) so that the built-up portion does not interfere with the seal lip.

<Third Embodiment>
16 and 17 are perspective views showing a magnetic encoder (3) according to a third embodiment of the present invention. As shown in both drawings, this magnetic encoder (3) is employed in a sealing device called a pack seal or a hub seal as in the second embodiment, and the inner diameter side (inner ring side) of the sealing device. The slinger (110) corresponds to the cored bar member (10) of the first embodiment.

  In this magnetic encoder (3), a rising piece (126) is formed on the outer peripheral edge of the core bar (120) of the slinger (110) so as to protrude to one surface side (outer surface side) in the axial direction. The rising piece (126) is formed so as to be inclined toward the inner diameter side, and the inner surface of the rising piece (126) is formed as an inclined surface inclined toward the inner diameter side. And the outer peripheral end surface of the scale molded body (140) of the rising piece (126) is configured to be joined to the inner surface of the rising piece (126) in an adapted state.

  Since other configurations are substantially the same as those of the second embodiment, the same or corresponding parts are denoted by the same or corresponding reference numerals, and redundant description is omitted.

  In the magnetic encoder (3) of the third embodiment, the same effect can be obtained as in the first and second embodiments. Furthermore, in this embodiment, a rising piece (126) is formed on the outer peripheral edge of the cored bar (120) in the slinger (110), and the outer peripheral end surface of the scale molded body (140) is formed on the rising piece (126). Since the outer peripheral end surface of the scale molded body (140) is locked to the rising piece (126) inclined toward the inner diameter side, the scale molded body (140) can be further peeled off in the axial direction. Thus, the scale molded body (140) can be tightly bonded to the slinger (110) in a more stable state.

<Example 1>
The magnetic encoder (1) of the same form was produced in the same manner as in the first embodiment shown in FIGS. At this time, the cored bar member (10) is made of SUS430, the thickness of the cored bar (20) is 0.6 mm, the depth of the radiating groove (21) is 0.25 mm, the radiating groove (21), etc. The fraction (number) was set to 90 (total number of poles 90). Furthermore, the radiation groove (21) was formed in the form of a fan-shaped groove in which both side wall inner surfaces (22) are arranged along the radiation (L) from the center of the core metal (20), as in the first embodiment.

  Further, as a plastic magnet material for forming the scale molded body (40), a resin composition containing 60% by volume of strontium ferrite (magnetic powder) with respect to polyamide 6 (binder resin) was used. Then, the resin composition is used as a molding material, the cored bar member (10) is used as an insert member, insert molding is performed in the same manner as in the first embodiment, and the cored bar member (10) is scaled with a thickness of 0.9 mm. A compact (40) was formed to produce the magnetic encoder of Example 1. In Example 1, no adhesive was used. That is, insert molding was performed without applying an adhesive to the resin molding surface (adhesion surface) of the core plate (10).

<Example 2>
Radiation grooves in the cored bar member were formed in the form of parallel grooves in which the inner surfaces of both side walls were parallel from the outer diameter end to the inner diameter end. Other than that was carried out similarly to the said Example 1, and produced the magnetic encoder of Example 2. FIG.

<Comparative Example 1>
As the core metal member, a core metal member having no flat surface and a flat core metal surface was used. Further, an adhesive was applied to the resin molding surface of the core metal member, and insert molding was performed in the same manner as described above. Other than that was carried out similarly to the said Example 1, and produced the magnetic encoder of the comparative example 1. FIG.

<Comparative example 2>
As a core metal member, a member having a flat core metal surface without a radiation groove was prepared. On the other hand, the same plastic magnet material as in Example 1 was injection molded to prepare a single scale molded body. And the scale molded object was affixed on the metal core surface of the metal core member using the adhesive. Other than that was carried out similarly to the said Example 1, and produced the magnetic encoder of the comparative example 2. FIG.

<Evaluation test>
Each of the magnetic encoders of the above examples and comparative examples was subjected to 1000 cycles of a thermal history impact test in which a cycle of heating at 150 ° C. for 30 minutes and cooling at −40 ° C. for 30 minutes was one cycle. Table 1 shows the test results and the main configuration of each magnetic encoder.

  As is apparent from Table 1, the magnetic encoders of Examples 1 and 2 related to the present invention showed no abnormalities such as cracks and cracks in the scale molded body even in the 1000-cycle thermal history impact test. It was. Therefore, it can be considered that the magnetic encoder of the embodiment can be used without any trouble even in a severe temperature environment.

  On the other hand, among the comparative examples that depart from the gist of the present invention, the magnetic encoder of Comparative Example 1 was cracked in the scale molded body at an early stage during the test and extremely inferior in heat resistance. . Further, in the magnetic encoder of Comparative Example 2, the scale molded body was cracked during the test and was inferior in heat resistance. Therefore, it can be considered that the magnetic encoders of Comparative Examples 1 and 2 are difficult to use in a severe temperature environment.

  Further, when the magnetic characteristics of the magnetic encoders of Examples 1 and 2 were inspected after the thermal hysteresis impact test, no change was observed in the magnetic characteristics, and good magnetic characteristics were maintained.

  Further, in the magnetic encoders of Examples 1 and 2 after the thermal hysteresis impact test, when the backlash of the scale formed body with respect to the core metal was observed in a state cooled to −40 ° C., the backlash was completely recognized in the magnetic encoder of Example 1. It was in close contact with the stable state. On the other hand, although the magnetic encoder of Example 2 was slightly rattled compared to that of Example 1, it was not problematic in practical use.

1 is a perspective view showing a magnetic encoder according to a first embodiment of the present invention. It is a perspective view which cuts and shows a part of magnetic encoder of a 1st embodiment. It is a perspective view which shows the metal core member applied to the magnetic encoder of 1st Embodiment. It is a perspective view which notches and shows a part of core metal member of 1st Embodiment. It is a perspective view which expands and shows a part of core metal member of a 1st embodiment. It is a top view which shows the metal core member of 1st Embodiment. It is a top view which expands and shows the part enclosed with the dashed-dotted line of FIG. It is a schematic diagram for demonstrating the groove | channel form of a radiation groove. It is a perspective view which notches and shows a part of core metal member which is the 1st modification of this invention. It is a perspective view which expands and shows a part of core metal member which is the 1st modification of this invention. It is a perspective view which notches and shows a part of magnetic encoder which is the 2nd modification of this invention. It is a perspective view which notches and shows a part of core metal member applied to the magnetic encoder of the 2nd modification. It is a perspective view for demonstrating a problem in the magnetic encoder of a 2nd modification. It is a perspective view which shows the magnetic encoder of the sealing device which is 2nd Embodiment of this invention. It is a perspective view which notches and shows a part of magnetic encoder of 2nd Embodiment. It is a perspective view which shows the magnetic encoder of the sealing device which is 3rd Embodiment of this invention. It is a perspective view which notches and shows a part of magnetic encoder of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1-3 ... Magnetic encoder 20 ... Core metal 21 ... Radiation groove 22 ... Side wall inner surface 25 ... Protrusion 40 for peeling prevention ... Scale molded object 41 ... Round molding part 42 ... Filling molding part 120 ... Core metal 121 ... Radiation groove 126 ... Standing piece 140 ... Scale molded body 142 ... Filling molded part C ... Core metal center L ... Virtual radiation

Claims (7)

A magnetic encoder comprising: an annular cored bar; and an annular scale formed body formed of a plastic magnet material provided on one surface of the cored bar and magnetized in multiple poles in the circumferential direction. ,
A plurality of radial grooves extending in the radial direction and opening in the inner diameter direction are formed side by side in the circumferential direction on one surface of the cored bar,
A magnetic encoder, wherein a filling molding portion made of a plastic magnet material filled in the radiation groove is formed integrally with the scale molding.   The magnetic encoder according to claim 1, wherein no adhesive is provided between the core metal and the scale molded body.   The inner surface of the side wall of the radiation groove is disposed on virtual radiation extending radially from the center of the core bar, and the width of the radiation groove is formed so as to become narrower toward the inner diameter direction. The magnetic encoder described.   4. The magnetic encoder according to claim 1, wherein an exfoliation preventing protrusion is provided on an inner surface of the side wall of the radiation groove to prevent the scale molded body from exfoliating in an axial direction.   5. The rising piece for locking the outer peripheral edge of the scale molded body to the outer peripheral end surface of the core metal to prevent the scale molded body from peeling off in the axial direction. The magnetic encoder according to any one of claims.   A wrap-around molded part made of a plastic magnet material is integrally formed on the inner peripheral part of the scale molded body, and the wrap-around molded part passes through the inner peripheral edge from one surface of the core metal and the other of the core metal. The magnetic encoder of any one of Claims 1-4 arrange | positioned so that it may wrap around to a surface. A magnetic encoder comprising an annular cored bar and an annular scale formed body formed of a plastic magnet material provided on one surface of the cored bar and magnetized in multiple poles in the circumferential direction is manufactured. A method for
Obtaining a ring-shaped cored bar in which a plurality of radial grooves extending along the radial direction and opened in the radial direction are arranged in a circumferential direction on one surface;
A plastic molded material is used as a molding material, and the cored bar is used as an insert member. By performing injection molding in a magnetic field, a filling molding part is formed by the molding material filled in the radiation groove. Forming a scale formed body integrally therewith to obtain a magnetic encoder.

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